Aircraft systems include software configurable components. These components often come in the form of mechanical boxes that contain electronics capable of processing and storing data, and commanding outputs. Such boxes include generator control units (GCUs), bus power control units (BPCUs), and various avionics systems. Varying versions of software may be available for a given box, but the software loaded on each box must be compatible with the other systems onboard the aircraft. Because of this, incompatibilities can arise if a unit is installed on an aircraft with a version of software that does not match that of the other systems onboard the aircraft.
An onboard file system may contain the current software versions for all of the software loadable boxes of the aircraft. Many of the loadable boxes can listen on a communications bus for the appropriate aircraft identifiers and software versions before commanding outputs or states to the aircraft. However, a box that lies in the power path of the aircraft may be responsible for commanding power to the onboard file system. It may not be safe to power the onboard file system through the power path box without first knowing the aircraft identifiers and current software versions. However, the onboard file system cannot provide identifiers and software versions to the power path box until it has been powered. This makes it difficult to automate the version compatibility check process when a box in the power path is installed.